U.S. Pat. No. 4,419,866, which is assigned to the same assignee as the present application, discloses a transport refrigeration system in which a Diesel engine which drives a refrigerant compressor may be selectively operated in either a continuous or a start-stop mode. In the start-stop mode, the Diesel engine is under the control of a refrigeration thermostat, being stopped and re-started as the temperature of a controlled space enters and leaves predefined temperature bands relative to a selected temperature set point.
U.S. Pat. No. 4,878,465, which is also assigned to the same assignee as the present application, discloses improved electrical control for automatically starting a Diesel engine, which simplified the control and improved the logic of the '866 patent. A thermistor in the engine coolant controls the engine pre-heat time. A battery monitor control module determines if the battery charge condition is at a level sufficient to permit the engine to stop. An electronic temperature control module or thermostat controls the temperature of the served space, similar to the '866 patent.
While the systems of the '866 and '465 patents perform well, it would be desirable, and it is an object of the present invention, to integrate and consolidate all of the functions of the separate control modules into one controlling function, such as provided by a computer, and more specifically a microprocessor, while further enhancing and improving the control of a transport refrigeration unit.
U.S. Pat. Nos. 4,663,725 and 4,918,932, which are assigned to the same assignee as the present application, disclose the use of microprocessor based refrigeration control for use with transport refrigeration systems, with the controlling functions being related to aspects of such systems other than the prime mover.